REACTOR PRESSURE VESSEL

PROBLEM TO BE SOLVED: To enable easy inspection and repair by attachably and detachably mounting a reactor core supporting structure for supporting an incore structure in the main body of a pressure vessel. SOLUTION: The lower part of the reactor core supporting structure 15 is composed of a cylindrical cylinder 16 and a shroud 17 and pieces of legs 18 which are supporting members are mounted at the bottom of this cylinder 16. Guide brackets 20 capable of fitting and detaining the legs 18 are welded and fixed to the lower end plate part 19 of the main body 12 of the pressure vessel. Further, horizontal support brackets 21 are projectingly disposed inward from the main body 12 of the pressure vessel. The intermediate parts of the cylinder 16 are projectingly provided with projecting parts 22 for fastening superposed on the front ends of the support brackets 21 from above. Screws 27 which can be screwed via washers with stoppers are disposed between threaded holes 23 formed at the support brackets 21 and the through-holes of the projecting parts 22 for fastening. As a result, the easy removal of the reactor core supporting structure 15 by removing the screws 27 is made possible and the inspection, etc., of the nuclear reactor vessel 14 are made possible.